<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>严格模式</title>
</head>
<body>
    <script>
        web = "xiasnn.com";

        function show(){
            // 严格模式只会向下查找，不会向上查找
            "use strict";
            function handle(){
                test = "skfjdkl";
            }
            handle();
        }

        show()

        function a(){
            b = "bbbbbbbbbbbbbb";
        }

        a();
    </script>
    
</body>
</html>